1. Field of the Invention
The present invention relates to a mobile communication system, and more particularly, to the improvement of connection of mobile base stations.
2. Description of the Related Art
A prior art mobile communication system includes a plurality of mobile base stations and a plurality of mobile control stations for carrying out call connection control between the mobile base stations and between the mobile base stations and public switched telephone networks. In this case, the mobile control stations are connected by using private circuits, to thereby speed up the call connection control. This will be explained later in detail.
As the number of mobile control stations is increased, a mesh connection therebetween becomes complex, thus increasing the manufacturing cost. In order to reduce the manufacturing cost, a hierarchical structure of mobile control stations has been adopted (see Kota Kinoshita: "System Network Technology", IEICE Proceeding, Vol. 73, No. 8, p. 814, FIG. 2, August 1990, Japan). In the hierarchical structure of mobile control stations, however, traffic density in upper-side mobile control stations is very large, thus locally creating a congested state therein. This also will be explained later in detail.